Tuesday, July 22, 2008

Will Viagra be Approved for Antidepressant-Related Sexual Dysfunction in Women?

Women with sexual dysfunction caused by the use of antidepressants experienced a reduction in adverse sexual effects with use of sildenafil, commonly known as the erectile dysfunction medication Viagra, according to a study in the July 23/30 issue of JAMA (JAMA. 2008;300[4]:395-404).

I could not verify that this study was funded by Pfizer in time for this post -- the principal author, H. George Nurnberg, M.D., of the University of New Mexico School of Medicine's Department of Psychiatry, declined to be interviewed. Dr. Nurnberg, however, has published other papers on related research for which he received funding from Pfizer (see, for example, "Sildenafil Citrate for the Management of Antidepressant-Associated Erectile Dysfunction"). The financial disclosure included in that published study states:

Dr. Nurnberg has served as a consultant to Pfizer, Eli Lilly,SmithKline, Bristol-Myers, and Glaxo; has received grant/research support from Pfizer, Eli Lilly, SmithKline, Bristol-Myers, Abbott, Lipha, Johnson & Johnson, Parke-Davis, andWyeth; and has served on the speakers bureau for Pfizer, EliLilly, SmithKline, Bristol-Myers, Abbott, Glaxo, and Wyeth.Dr. Hensley has received grant/research support from Forest,Pfizer, and Hoffman-LaRoche and has received honoraria fromand has served on the speakers or advisory boards for Forest,Pfizer, and Wyeth.

Studies like this could be used to buttress Pfizer's expansion of its Viagra franchise by seeking FDA approval for new indications for Viagra. Currently, Viagra is approved only for marketing as a treatment for men with erectile dysfunction (ED). There has been some signs that Pfizer is seeking other indications for Viagra, including premature ejaculation (see "PEED: A New Viagra Franchise?").

The holy grail, however, would be an indication for enhancing women's sexual function. Initial trials of Viagra in women proved highly disappointing, however. "True, the drug enhanced engorgement of vaginal tissue, just as it had of the penis," reports the NY Times, "but that extra bit of pelvic swelling did nothing to amplify women’s desire for or enjoyment of sex" (see "The Search for the Female Equivalent of Viagra")

The next best thing would be to treat sexual dysfunction in women who take antidepressants! And there are a LOT of women in this category! "Do the math," says Jim Edwards in his blog post "Worst Side Effect Ever: The 'Pleasureless Orgasm.'"

"SSRI antidepressants — such as Paxil, Lexapro, Zoloft, Luvox and Prozac — have rates of 'decreased libido, delayed orgasm, anorgasmia, erectile dysfunction, and difficulties with arousal, of between 36 and 70%,' according to a new study," says Edwards.

Edwards continues: "According to Scientific American, close to 10% of Americans are on antidepressants. Let’s make it easy and say that’s 30 million of 300 million yanks. Of those, possibly 23 million are walking around in a state of sexual frustration. And they have partners — so that’s somewhere in the neighborhood of a possible 46 million of us who are inexplicably tetchy and bad tempered on most days."

Of that 46 million, I'd hazard a guess that 70% or 32 million are women. This is potentially a tremendously huge new market for Viagra -- much larger than the puny premature ejaculation market!

I suspect it may be pretty easy for Pfizer to get the FDA to approve Viagra for treatment of antidepressant-related sexual dysfunction in women. As the authors of the study note "By treating this bothersome treatment-associated adverse effect in patients who have been effectively treated for depression, but need to continue on their medication to avoid relapse or recurrence, patients can remain antidepressant-adherent, reduce the current high rates of premature medication discontinuation, and improve depression disease management outcomes."

"Improving outcomes" is currently the magic key that can open many doors at FDA.

Once Viagra is approved for anti-depressant sexual dysfunction in women, one door that definitely will open is the door to off-label use of Viagra by all women as a party drug no matter if it works or not for that purpose.

Update: Bloomberg.com reports that Pfizer sponsored the study through a grant but "has no plans to seek regulatory approval for Viagra as a treatment for female sexual dysfunction," according to spokeswoman Sally Beatty in a July 21 e-mail. The company is looking into other treatment approaches for women, she said (see "Viagra May Help Women Restore Orgasms Lost to Antidepressants").

Hmmm...we'll see. Maybe there will be a groundswell of demand from women on anti-depressants for Pfizer to seek approval. I suggest that we keep an eye out for off-label prescriptions for Viagra written by doctors for women on anti-depressants. Unfortunately for less affluent women, medical insurance and Medicare won't pay for unapproved uses of drugs. I also predict an enlarged black market for Viagra and more Viagra spam e-mail messages being sent to women!

About the Author

Pharmaguy™ (@pharmaguy) is a "constructive critic" of the pharmaceutical industry. He is not shy about giving his opinion, which is respected by many insiders who share some of his views but who are unable to voice them on their own.